In some fan engines (e.g., “propfan” engines), an axis of a rotating propeller is parallel to or coaxial with an axis of the gas engine. In some such engines, the propeller may have a fixed pitch or a variable pitch. Certain variable pitch gas turbine engines include a thrust reverse feature for redirecting a flow of air through or around the engine to generate a reverse motive force or thrust. Generally, in order to generate a reverse thrust, the pitch of the propellers is rotated such that air is drawn from a rearward or aft portion of the engine. As the propellers rotate about a central axis, the reverse flow air provides thrust in a direction opposite of a normal operation, i.e., from aft to forward instead of the normal forward to aft. During reverse thrust, air is forced around the engine before it is drawn into a typical forward inlet of a core engine compressor. Upon entering the compressor inlet, air flows in a relatively normal direction, i.e., from forward to aft. Although air is provided into a typical location (the compressor inlet) during reverse thrust, significant and undesired swirl or flow distortion may be introduced into the airflow. Moreover, since most engines are primarily designed for normal flow (forward to aft), existing engines are typically only streamlined in that direction. Various support elements or the inlet to the engine may cause aft to forward airflow to swirl, detrimentally affecting the compressor's performance, as well as performance of the whole engine.
Accordingly, an improved reversible gas turbine engine is desired. In particular, a gas turbine engine that reduced the amount of flow distortion introduced into reversed airflow would be advantageous.